JPH02120062U

JPH02120062U -

Info

Publication number: JPH02120062U
Application number: JP2924489U
Authority: JP
Priority date: 1989-03-15
Filing date: 1989-03-15
Publication date: 1990-09-27

Description

[Brief explanation of drawings]

第１図は実施例のＣＯ検出装置の回路図、第２
図はＣＯ検出信号の処理を表す詳細回路図、第３
図はガスセンサの異常検出回路を表す詳細回路図
、第４図はヒータの異常検出回路を表す詳細回路
図。第５図はＣＯの検出過程を示すフローチヤー
ト、第６図はＣＯの検出過程を示す動作波形図で
、１はガス濃度を、２はヒータ電圧を、３はセン
サ出力を、４〜６はＬＥＤの動作を、７はブザー
の動作を、８は外部出力の波形を、表す。第７図〜第９図はガスセンサの出力波形を表し
、各図において１はガスセンサ出力を、２はヒー
タ電圧を表す。第１０図はガスセンサの異常検出の過程を表す
フローチヤート、第１１図はその動作波形図で、
１はガスセンサの出力波形を、２はヒータ電圧を
、３は負荷抵抗の切り替えを表す。第１２図はヒータの異常検出の過程を表すフロ
ーチヤート、第１３図はその動作波形図で、１は
抵抗Ｒ４，Ｒ５の電圧波形を、２はヒータ電圧を
、３は比較回路Ｃ１，Ｃ２の出力波形を表す。図において、２はガスセンサ、４，６はヒータ
、８は金属酸化物半導体、２０はトランス、２４
はマイクロコンピユータ。 Figure 1 is a circuit diagram of the CO detection device of the embodiment, Figure 2 is a circuit diagram of the CO detection device of the embodiment.
The figure is a detailed circuit diagram showing the processing of the CO detection signal.
The figure is a detailed circuit diagram showing a gas sensor abnormality detection circuit, and FIG. 4 is a detailed circuit diagram showing a heater abnormality detection circuit. Figure 5 is a flowchart showing the CO detection process, and Figure 6 is an operation waveform diagram showing the CO detection process, where 1 represents the gas concentration, 2 represents the heater voltage, 3 represents the sensor output, and 4 to 6 represent the sensor output. 7 represents the operation of the LED, 7 represents the operation of the buzzer, and 8 represents the waveform of the external output. 7 to 9 represent output waveforms of the gas sensor, and in each figure, 1 represents the gas sensor output, and 2 represents the heater voltage. Figure 10 is a flowchart showing the process of detecting an abnormality in the gas sensor, and Figure 11 is its operating waveform diagram.
1 represents the output waveform of the gas sensor, 2 represents the heater voltage, and 3 represents switching of the load resistance. Fig. 12 is a flowchart showing the process of heater abnormality detection, and Fig. 13 is its operating waveform diagram, where 1 is the voltage waveform of resistors R4 and R5, 2 is the heater voltage, and 3 is the comparator circuit C1 and C2. Represents the output waveform. In the figure, 2 is a gas sensor, 4 and 6 are heaters, 8 is a metal oxide semiconductor, 20 is a transformer, and 24
is a microcomputer.

Claims

[Scope of Claim for Utility Model Registration] In a device that detects CO by alternating the temperature of a gas sensor between a high temperature range and a low temperature range and compares the gas sensor output in the low temperature range with a detection threshold, A means for detecting hydrogen from the peak of the gas sensor output in the first half, a means for changing the detection threshold when hydrogen is detected, and a means for detecting gas sensor abnormalities from the presence or absence of changes in the gas sensor output in synchronization with temperature changes. 1. A CO detection device, comprising: a means for detecting CO.